Synthesis and characterization of silver nanoarticles from extract of Eucalyptus citriodora

The primary motivation for the study to develop simple eco-friendly green synthesis of silver nanoparticles using leaf extract of Eucalyptus citriodora as reducing and capping agent. The green synthesis process was quite fast and silver nanoparticles were formed within 0.5 h. The synthesis of the particles was observed by UV-visible spectroscopy by noting increase in absorbance. Characterization of the particles was carried out by X-ray diffraction, FTIR and electron microscopy. The developed nanoparticles demonstrated that E. citriodora is good source of reducing agents. UV-visible absorption spectra of the reaction medium containing silver nanoparticles showed maximum absorbance at 460 nm. FTIR analysis confirmed reduction of Ag+ to Ag0 atom in silver nanoparticles. The XRD pattern revealed the crystalline structure of silver nanoparticles. The SEM analysis showed the size and shape of the nanoparticles. The method being green, fast, easy and cost effective can be recommended for large scale production of AgNPs for their use in food, medicine and materials

Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO3_3

Improvement in magnetic and electrical properties of multiferroic BiFeO$_3$ in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles of different sizes ranging from $\sim$ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe$^{2+}$ state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO$_3$ nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for $\sim$ 49 nm Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO$_3$.Comment:

Prevalence of vitamin D deficiency in Pakistan and implications for the future

Background and aims: Vitamin D deficiency (25-hydroxyvitamin D - VitDD) affects over one billion people worldwide. VitDD results in progression of osteoporosis as well as other conditions. Previous studies have shown high rates of VitDD in Pakistan despite appreciable levels of sunshine. However, none have assessed VitDD across all age groups, genders, incomes and locations to guide future strategies. Methods: Questionnaire and blood sampling among 4830 randomly selected citizens. Results: High levels of VitDD among all age groups, genders, income levels and locations. 53.5% had VitDD, 31.2% had insufficient Vitamin D and only 15.3% normal Vitamin D. Conclusion: High rates of VitDD in Pakistan despite high levels of sunshine and previous Food Acts asking for food fortification with Vitamin D. Public health strategies are needed to address high VitDD rates, including food fortification, i.e. nurture, alongside increasing exposure to sunlight, i.e. nature. This will involve all key stakeholder groups

The Effectiveness of Co-curricular Activities on Academic Achievements of Secondary School Students in District Abbottabad Pakistan - A Case Study

This research was conducted to examine the effect of co-curricular activities on academic achievements of secondary school students in District Abbottabad. The research is experimental in nature, pre-test Post's test equivalent group design was selected for this purpose. In this study, an achievement test covering four chapters of mathematics and four lessons of English was used as measuring instrument. Depending upon pre-test scores, 200 students of 10th class were divided into two equal groups (n=100) named as experimental group and control group. The experimental group was involved in co-curricular activities and the control group did not participate in any activity beyond the classroom. There were two types of co-curricular activities. First physical i.e., games, athletics and P.T (physical training) etc and the other was debates, drama speeches etc. The experimental group carried out activities for forty minutes daily for twelve weeks. The post-test was administered after twelve weeks. The pre-test and post-test scores of the experimental and control groups served as data for this study. The analysis of data revealed that on the whole, experimental groups showed better performance than controlled group. Hence the ultimate results of the study indicated that co-curricular activities can contribute for enhancing academic achievements of the secondary school students. Keywords: Co-curricular activities, Academics achievement